Polycondensation polymers typically follow step-growth kinetics assuming all functional groups are equally likely to react with one another. If the reaction rates with the chain end can be selectively accelerated, living polymers can be obtained. Here we report on two chlorophosphonium iodide reagents that have been synthesized from triphenylphosphine and tri(o-methoxyphenyl)phosphine. The former activates aromatic carboxylic acids as acid chlorides in the presence of secondary aromatic amines and the latter even in the presence of primary aromatic amines. These reagents allow p-aminobenzoic acid derivatives to form solution-stable activated monomers that polymerize in a living fashion in the presence of amine initiators. Other aryl amino acids and even dimers of aryl amino acids can be polymerized in a living fashion when slowly added to the phosphonium salt in the presence of an amine initiator. Diblock copolymers and triblock terpolymers of aryl amino acids can be prepared even in the presence of electrophilic functional groups.

假设所有官能团彼此反应的可能性相同，缩聚聚合物通常遵循逐步增长动力学。如果可以选择性地加快与链端的反应速率，则可以获得活性聚合物。在这里，我们报告了由三苯基膦和三（邻甲氧基苯基）膦合成的两种碘化氯鏻试剂。前者在芳族仲胺存在下将芳族羧酸活化为酰氯，而后者甚至在芳族伯胺存在下也能活化。这些试剂允许p-氨基苯甲酸衍生物形成溶液稳定的活化单体，在胺引发剂存在下以活性方式聚合。当在胺引发剂存在下缓慢添加到鏻盐中时，其他芳基氨基酸甚至芳基氨基酸的二聚体可以以活性方式聚合。甚至在存在亲电官能团的情况下也可以制备芳基氨基酸的二嵌段共聚物和三嵌段三元共聚物。